Some heads up from my side there will be a tool in the very far future which will break the limits which the game has. Quantumpencil is working on it, the name is Sister Ray. More weapons will be a piece of cake. Nevertheless atm we can't mod the game as much as we want to and if SR will be ready one day isn't also sure to 100%. But I cross my fingers.
Oh yee of little faith. It's definitely coming. I'm having to work on it a little more slowly than I expected but my motivation has not faltered.
Anyway, everything you have mentioned is fairly doable except for the first, which is possible but I'll have to literally have the whole battle engine re-implemented first (and probably much more than just that) I will be adding in battle party member switching (think FFX) though, but the game hardcodes checks and loops over the party as by index range bounded above by 3 like 391513053 times, so even with my extensive rewrite of the engine it'll take me years to have all of that code under my control so I can actually expand the number of party members.
2 is trivial, it's been done several times. I've done it and DLPB has done it.
3 just hook in on battle end/reset and set it to 0, shouldn't be that hard.
4: Not that difficult if you understand battle engine well, I've basically solved all the parts of this (and much more actually, I can get entirely new animations into the game and have them played however I like, so limit break model animations are usable outside of the context of the "Limit Break" command as a subproblem)and this will be a default option with sister ray.
5 is possible and not all that difficult. The simplest implementation would to to disable atb switch (I've already got the entire battle menu re-implemented w/ a widget system so this is easy) which is bound to an input handler in the battle menu input handler routine, and then not update the ATB gauge when the menu state-machine is set to select -- which also takes place in a battle menu update handler (The one associated to state 0 of the state machine), I already control all this code. Could even add a "pass" command if you don't want to act with a quicker ATB recovery divisor than if an action is taken ti simulate "Wait" in that kind of game. You could then create a new widget ala FFX and display the turn order without too much trouble.
6 hard to do "properly" but possible. I've solved many sub problems but not quite there yet (I've rewritten the battle/menu inventories and got the game reading from my own weapon registries, so more weapons/items/gear is no problem EXCEPT that you can't easily give them to your party outside of SR code.) I believe the solution here that i'll use is modifying Makou Reactor so that it outputs an intermediary form of the field scripts which contain symbols representing items/weapons a specific modder has added, and then just substitute in the true indexes in the various registries I've got holding all this information in an extensible way.
7 is possible but very time consuming. Better tooling is needed
